The present invention relates to a method of manufacturing shaped and reinforced fabrics, and more particularly to a method of manufacturing shaped and reinforced fabrics continuously in alternation, the fabric being constituted by composite elements which are constituted by a membrane, impervious for example, which encases reinforcing elements, threads for example, the elements constituting the fabric being capable of being shaped in three dimensions so that the fabric has a desired shape in three dimensions.
Reinforced and shaped fabrics are used in all cases where a fabric has to be reinforced generally and in particular when a fabric has to be reinforced in particular directions which are determined by the forces that act on the fabric. By way of example, when a fabric acted on greatly by forces comprises fixing eyelets at the location of its corners or elsewhere, reinforcements may be necessary to distribute the forces, maintain the shape and avoid tears. Moreover, if large forces act between one or other of the eyelets, reinforcements may be necessary in the direction of the forces.
In many cases, it is necessary for the fabric to have particular shapes in three dimensions whether for reasons of performance or for aesthetic reasons.
The manufacture of high-performance reinforced and shaped fabrics is subject to several parameters including of course commercial criteria which require that a fabric must be high-performance, as light as possible and of course with a price as low as possible.
Many embodiments of reinforced and shaped fabrics and of reinforced and shaped fabric manufacture are known but they all have many drawbacks.
A basic drawback of all the known high-performance reinforced and shaped fabrics is that the structure of the fabric is constituted by an assembly of elements of the sandwich type, that is to say the fabric consists of at least three components, these being the reinforcing elements which are assembled by bonding in a sandwich between two polymerised plastic sheets, for example. This type of fabric construction is expensive and has a fairly heavy weight. The polymerised plastic sheets are semi-rigid and may not allow local deformations. The overall shape of the fabric must allow a desired shape to be obtained over the whole dimension of the fabric which consequently requires moulds with the total size of the sail which are very expensive. These manufacturing methods with total-size moulds have several drawbacks, one of the greatest of which is the cost which is inevitably carried over to the end product. Another drawback is the space requirement of these moulds which require very large production premises. Moreover, the large cost of the tools implies a lack of flexibility when changes in shape are necessary which slows down the development phases and makes them very expensive. As the reinforcing threads are generally each placed in one piece with these embodiments, the positioning is very tricky.
Other known embodiments are implemented by assembling several fabric panels from different cuts, the panels being assembled together by sewing or bonding. The location of the sewing is fragile and requires reinforcing panels themselves added on by sewing. The forces to which the fabric is subjected are therefore dependent on the strength of the sewing at these locations which, as said, has the drawback of requiring reinforcing panels which contribute towards increasing the overall weight of the fabric. Moreover, at the locations of the sewing and the reinforcing panels, the fabric is less flexible than the other panels of the fabric, which causes many creases and fatigue of the materials when the fabric takes the desired shape, which is unsightly and can reduce the performance of the fabric for certain forms of use.